Influence of Precursor Chemistry on Synthesis of Silicon-Carbon-Germanium Alloys

1995 ◽  
Vol 377 ◽  
Author(s):  
Michael Todd ◽  
John Kouvetakis ◽  
Phillip Matsunaga ◽  
D. Chandrasekhar ◽  
David Smith

ABSTRACTWe describe the synthesis and use of the novel molecular precursors C (SiH3) 4, CH3GeH3and SiH3GeH3 to generate silicon-carbon-germanium materials by ultrahigh vacuum chemical vapor deposition. By using these precursors in reactions with S1H4 and GeH4 between 470°C and 650°C we obtained: 1) heteroepitaxial Si1-x-y. GexCy (y=0.04–0.06) alloys with C (SiH3) 4; (2) polycrystalline alloys with carbon compositions ranging from 2–14 at.% with CH3GeH3; (3) mixtures of diamond cubic nanocrystals (Ge, Si1-xGex) and amorphous SiC with SiH3CH2GeH3. The effect of the precursor chemistry on composition, crystallinity, and microstructure of the materials as characterized by Rutherford backscattering spectroscopy (RBS), secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM) is discussed.

1995 ◽  
Vol 398 ◽  
Author(s):  
Kenneth M. Kramer ◽  
Michael O. Thompson

ABSTRACTIon implantation of carbon into single-crystal silicon followed by excimer laser irradiation was used to create supersaturated, epitaxial SixC1-x. films. Crystallization proceeded from the underlying single-crystal silicon through the carbon containing layers at velocities of approximately 5 m/s. Characterization by high-resolution x-ray diffraction and Fourier-transform infrared absorption indicate that the carbon is found predominantly on substi-tutional lattice sites for concentrations up to 1.4 at.% C. Secondary-ion mass spectrometry profiles and numerical mass transfer calculations were used to estimate the diffusion coefficient of carbon in the liquid as 2-3 × 10−4cm2/s with a segregation coefficient greater than 0.4. Unusual diffusion behavior was observed for the carbon at 1.4 at.% C. At higher concentrations, evidence of SiC precipitates was observed in transmission electron microscope images and FTIR absorption spectra.


1996 ◽  
Vol 441 ◽  
Author(s):  
D. Chandrasekhar ◽  
J. Kouvetakis ◽  
J. Mc Murran ◽  
M. Todd ◽  
David J. Smith

AbstractNovel precursor chemistry and ultrahigh-vacuum chemical vapor deposition have been used to deposit Si1-yCyth in films on (001) Si substrates. Films with carbon compositions ranging up to 20 at. % were deposited at substrate temperatures of 600–750°C using interactions of C(SiH3)4 or C(SiH2Cl)4 (C-H free precursors incorporating Si4C tetrahedra) and SiH4 gas mixtures. The composition of the resulting materials was obtained by Rutherford backscattering spectrometry including carbon resonance analysis. Cross-sectional transmission electron microscopy and infrared spectroscopy were used to provide microstructural and bonding information respectively. The effect of precursor chemistry on the composition and structure of the materials is discussed.


1999 ◽  
Vol 557 ◽  
Author(s):  
W. Qin ◽  
D. G. Ast ◽  
T. I. Kamins

AbstractThe segregation of phosphorus to grain boundaries in phosphorus implanted Si0.87Ge0.13 films, deposited by chemical vapor deposition (CVD), was directly observed by scanning transmission electron microscopy (STEM) with energy dispersive x-ray (EDX) microanalysis. The segregation was determined to be a thermal equilibrium process by measuring and comparing the average phosphorus concentrations at the grain boundaries in Si0.87Ge0.13 films subjected to 700, 750 or 800°C annealing, following the implantation and 1000°C annealing processes. The measured segregation energy was 0.28 eV/atom. No Ge segregation was found at grain boundaries in phosphorus implanted Si0.87Ge0.13 films by STEM x-ray microanalysis. Neither was evidence shown by STEM microanalysis that Ge segregated to grain boundaries in intrinsic Si1-xGex films with x = 0.02, 0.13 and 0.31. Secondary ion mass spectrometry (SIMS) analysis showed that these intrinsic Si1-xGex films contained 1019 to 4 × 1019/cm-3H, depending on the deposition temperature.


1992 ◽  
Vol 262 ◽  
Author(s):  
J.W. Honeycutt ◽  
J. Ravi ◽  
G. A. Rozgonyi

ABSTRACTThe effects of Ti and Co silicidation on P+ ion implantation damage in Si have been investigated. After silicidation of unannealed 40 keV, 2×1015 cm-2 P+ implanted junctions by rapid thermal annealing at 900°C for 10–300 seconds, secondary ion mass spectrometry depth profiles of phosphorus in suicided and non-silicided junctions were compared. While non-silicided and TiSi2 suicided junctions exhibited equal amounts of transient enhanced diffusion behavior, the junction depths under COSi2 were significantly shallower. End-of-range interstitial dislocation loops in the same suicided and non-silicided junctions were studied by planview transmission electron microscopy. The loops were found to be stable after 900°C, 5 minute annealing in non-silicided material, and their formation was only slightly effected by TiSi2 or COSi2 silicidation. However, enhanced dissolution of the loops was observed under both TiSi2 and COSi2, with essentially complete removal of the defects under COSi2 after 5 minutes at 900°C. The observed diffusion and defect behavior strongly suggest that implantation damage induced excess interstitial concentrations are significantly reduced by the formation and presence of COSi2, and to a lesser extent by TiSi2. The observed time-dependent defect removal under the suicide films suggests that vacancy injection and/or interstitial absorption by the suicide film continues long after the suicide chemical reaction is complete.


Author(s):  
Jen-Inn Chyi ◽  
C. -M. Lee ◽  
C.C. Chuo ◽  
G. C. Chi ◽  
G. T. Dang ◽  
...  

Undoped, 4µm thick GaN layers grown by Metal Organic Chemical Vapor Deposition were used for fabrication of high stand off voltage (356 V) Schottky diode rectifiers. The figure of merit VRB2/RON, where VRB is the reverse breakdown voltage and RON is the on-resistance, was ~ 4.53 MW-cm−2 at 25°C. The reverse breakdown voltage displayed a negative temperature coefficient, due to an increase in carrier concentration with increasing temperature. Secondary Ion Mass Spectrometry measurements showed that Si and O were the most predominant electrically active impurities present in the GaN.


Author(s):  
В.В. Привезенцев ◽  
В.С. Куликаускас ◽  
В.А. Скуратов ◽  
О.С. Зилова ◽  
А.А. Бурмистров ◽  
...  

AbstractSingle-crystal n -Si(100) wafers are implanted with ^64Zn^+ ions with an energy of 50 keV and dose of 5 × 10^16 cm^–2. Then the samples are irradiated with ^132Xe^26+ ions with an energy of 167 MeV in the range of fluences from 1 × 10^12 to 5 × 10^14 cm^–2. The surface and cross section of the samples are visualized by scanning electron microscopy and transmission electron microscopy. The distribution of implanted Zn atoms is studied by time-of-flight secondary-ion mass spectrometry. After irradiation with Xe, surface pores and clusters consisting of a Zn–ZnO mixture are observed at the sample surface. In the amorphized subsurface Si layer, zinc and zinc-oxide phases are detected. After irradiation with Xe with a fluence of 5 × 10^14 cm^–2, no zinc or zinc-oxide clusters are detected in the samples by the methods used in the study.


1988 ◽  
Vol 126 ◽  
Author(s):  
P. Mel ◽  
S. A. Schwarz ◽  
T. Venkatesan ◽  
C. L. Schwartz ◽  
E. Colas

ABSTRACTTe enhanced mixing of AlAs/GaAs superlattice has been observed by secondary ion mass spectrometry. The superlattice sample was grown by organometallic chemical vapor deposition and doped with Te at concentrations of 2×1017 to 5×1018 cm−.3 In the temperature range from 700 to 1000 C, a single activation energy for the Al diffusion of 2.9 eV was observed. Furthermore, it has been found that the relationship between the Al diffusion coefficient and Te concentration is linear. Comparisons have been made between Si and Te induced superlattice mixing.


2000 ◽  
Vol 650 ◽  
Author(s):  
Te-Sheng Wang ◽  
A.G. Cullis ◽  
E.J.H. Collart ◽  
A.J. Murrell ◽  
M.A. Foad

ABSTRACTBoron is the most important p-type dopant in Si and it is essential that, especially for low energy implantation, both as-implanted B distributions and those produced by annealing should be characterized in very great detail to obtain the required process control for advanced device applications. While secondary ion mass spectrometry (SIMS) is ordinarily employed for this purpose, in the present studies implant concentration profiles have been determined by direct B imaging with approximately nanometer depth and lateral resolution using energy-filtered imaging in the transmission electron microscopy. The as-implanted B impurity profile is correlated with theoretical expectations: differences with respect to the results of SIMS measurements are discussed. Changes in the B distribution and clustering that occur after annealing of the implanted layers are also described.


2006 ◽  
Vol 527-529 ◽  
pp. 625-628
Author(s):  
Hun Jae Chung ◽  
Sung Wook Huh ◽  
A.Y. Polyakov ◽  
Saurav Nigam ◽  
Qiang Li ◽  
...  

Undoped 6H- and 4H-SiC crystals were grown by Halide Chemical Vapor Deposition (HCVD). Concentrations of impurities were measured by various methods including secondary-ion-mass spectrometry (SIMS). With increasing C/Si ratio, nitrogen concentration decreased and boron concentration increased as expected for the site-competition effect. Hall-effect measurements on 6H-SiC crystals showed that with the increase of C/Si ratio from 0.06 to 0.7, the Fermi level was shifted from Ec-0.14 eV (nitrogen donors) to Ev+0.6 eV (B-related deep centers). Crystals grown with C/Si > 0.36 showed high resistivities between 1053 and 1010 4cm at room temperature. The high resistivities are attributed to close values of the nitrogen and boron concentrations and compensation by deep defects present in low densities.


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